They discover a wasp that converts their araas into zombie drones

A recently discovered wasp species in the Ecuadorian Amazon transforms a "social" spider into a zombie drone that left its colony to comply with the wasp's orders .

This is the intrepid real discovery of researchers from the University of British Columbia, who detail the first example of a manipulative relationship between a new wasp of the species Zatypota and a social spider Anelosimus eximius in a study recently published in Ecological Entomology .

"Wasps manipulating the behavior of spiders have already been observed before, but not at such a complex level," said Philippe Fernández-Fournier, lead author of the study and former master's student in the department of zoology of UBC. "Not only does this wasp target a social species of spider, but it makes her abandon her colony, which she rarely does."

Fernández-Fournier was in Ecuador studying different types of parasites that live in spider nests Anelosimus eximius one of the world's 25 so-called "social spider species" . They are known to live together in large colonies, cooperate in catching prey, share the homework of the parents and seldom move away from their nests in the form of a basket.

When Fernández-Fournier saw that some spiders had been infected. a parasitic larva and saw them moving away from their colonies to spin closed nets of densely spun silk and pieces of foliage, he was perplexed. "It was very strange because they usually do not, so I started taking notes," he said.

Intrigued, he cautiously brought back some of the structures, called "cocoon cloths," to the lab to see what was coming out of the depths. To his surprise, it was a wasp.

"These wasps have an elegant appearance," said Samantha Straus, co-author of the study and a student in the Department of Zoology at the University of British Columbia. "But then, they become more brutal."

Using data collected in Ecuador for different projects between 2012 and 2017, researchers began to reconstruct the life cycle of the wasp and its parasitic relationship with the spider.

They found it just as fascinating and horrifying: after an adult female wasp laid an egg in the abdomen of a spider, the larva hatched and s'. attaches to his unfortunate host, the arachnid. Then, presumably, it feeds on the haemolymph, similar to the blood of the spider, which grows and takes the body slowly. The spider now "zombified" is leaving the colony and spinning a cocoon through the larva before patiently waiting to be killed and eaten. After being feasted on the spider, the larva enters its protected cocoon and comes out completely formed nine to eleven days later.

In other similar cases of parasitism, it is known that wasps target solitary species of spiders such as orb weavers and manipulate them into behaviors that are in their normal repertoire.

"But this change in behavior is serious ," said Straus. "The wasp completely removes the behavior and brain of the spider and makes it do something that it would never do, like leaving its nest and creating a completely different structure, which is very dangerous for these little ones. spiders. "

Wasps do this, but scientists believe that this can be caused by an injection of hormones that make the spider think that it is at a different stage of life or that It is scattered from the colony.

"We think that wasps are targeted at these social spiders because it provides a large stable host colony and a source of food," Straus said. "We also discovered that the larger the spider colony, the more likely it was that these wasps would report it."

Straus, now wearing a wasp tattoo, will return to Ecuador to investigate the return of the wasps to the same wasps. Spider colonies generation after generation and what evolutionary advantage they could present. Meanwhile, wasps will likely continue their main role in the worst nightmares of spiders.